linux-stable.git/net, branch v5.7.8

hsr: avoid to create proc file after unregister

2020-07-09T07:39:33+00:00

[ Upstream commit de0083c7ed7dba036d1ed6e012157649d45313c8 ]

When an interface is being deleted, "/proc/net/dev_snmp6/"
is deleted.
The function for this is addrconf_ifdown() in the addrconf_notify() and
it is called by notification, which is NETDEV_UNREGISTER.
But, if NETDEV_CHANGEMTU is triggered after NETDEV_UNREGISTER,
this proc file will be created again.
This recreated proc file will be deleted by netdev_wati_allrefs().
Before netdev_wait_allrefs() is called, creating a new HSR interface
routine can be executed and It tries to create a proc file but it will
find an un-deleted proc file.
At this point, it warns about it.

To avoid this situation, it can use ->dellink() instead of
->ndo_uninit() to release resources because ->dellink() is called
before NETDEV_UNREGISTER.
So, a proc file will not be recreated.

Test commands
    ip link add dummy0 type dummy
    ip link add dummy1 type dummy
    ip link set dummy0 mtu 1300

    #SHELL1
    while :
    do
        ip link add hsr0 type hsr slave1 dummy0 slave2 dummy1
    done

    #SHELL2
    while :
    do
        ip link del hsr0
    done

Splat looks like:
[ 9888.980852][ T2752] proc_dir_entry 'dev_snmp6/hsr0' already registered
[ 9888.981797][    C2] WARNING: CPU: 2 PID: 2752 at fs/proc/generic.c:372 proc_register+0x2d5/0x430
[ 9888.981798][    C2] Modules linked in: hsr dummy veth openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6x
[ 9888.981814][    C2] CPU: 2 PID: 2752 Comm: ip Tainted: G        W         5.8.0-rc1+ #616
[ 9888.981815][    C2] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 9888.981816][    C2] RIP: 0010:proc_register+0x2d5/0x430
[ 9888.981818][    C2] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 65 01 00 00 49 8b b5 e0 00 00 00 48 89 ea 40
[ 9888.981819][    C2] RSP: 0018:ffff8880628dedf0 EFLAGS: 00010286
[ 9888.981821][    C2] RAX: dffffc0000000008 RBX: ffff888028c69170 RCX: ffffffffaae09a62
[ 9888.981822][    C2] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88806c9f75ac
[ 9888.981823][    C2] RBP: ffff888028c693f4 R08: ffffed100d9401bd R09: ffffed100d9401bd
[ 9888.981824][    C2] R10: ffffffffaddf406f R11: 0000000000000001 R12: ffff888028c69308
[ 9888.981825][    C2] R13: ffff8880663584c8 R14: dffffc0000000000 R15: ffffed100518d27e
[ 9888.981827][    C2] FS:  00007f3876b3b0c0(0000) GS:ffff88806c800000(0000) knlGS:0000000000000000
[ 9888.981828][    C2] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9888.981829][    C2] CR2: 00007f387601a8c0 CR3: 000000004101a002 CR4: 00000000000606e0
[ 9888.981830][    C2] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 9888.981831][    C2] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 9888.981832][    C2] Call Trace:
[ 9888.981833][    C2]  ? snmp6_seq_show+0x180/0x180
[ 9888.981834][    C2]  proc_create_single_data+0x7c/0xa0
[ 9888.981835][    C2]  snmp6_register_dev+0xb0/0x130
[ 9888.981836][    C2]  ipv6_add_dev+0x4b7/0xf60
[ 9888.981837][    C2]  addrconf_notify+0x684/0x1ca0
[ 9888.981838][    C2]  ? __mutex_unlock_slowpath+0xd0/0x670
[ 9888.981839][    C2]  ? kasan_unpoison_shadow+0x30/0x40
[ 9888.981840][    C2]  ? wait_for_completion+0x250/0x250
[ 9888.981841][    C2]  ? inet6_ifinfo_notify+0x100/0x100
[ 9888.981842][    C2]  ? dropmon_net_event+0x227/0x410
[ 9888.981843][    C2]  ? notifier_call_chain+0x90/0x160
[ 9888.981844][    C2]  ? inet6_ifinfo_notify+0x100/0x100
[ 9888.981845][    C2]  notifier_call_chain+0x90/0x160
[ 9888.981846][    C2]  register_netdevice+0xbe5/0x1070
[ ... ]

Reported-by: syzbot+1d51c8b74efa4c44adeb@syzkaller.appspotmail.com
Fixes: e0a4b99773d3 ("hsr: use upper/lower device infrastructure")
Signed-off-by: Taehee Yoo 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

hsr: remove hsr interface if all slaves are removed

2020-07-09T07:39:32+00:00

[ Upstream commit 34a9c361dd480041d790fff3d6ea58513c8769e8 ]

When all hsr slave interfaces are removed, hsr interface doesn't work.
At that moment, it's fine to remove an unused hsr interface automatically
for saving resources.
That's a common behavior of virtual interfaces.

Signed-off-by: Taehee Yoo 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

mptcp: drop MP_JOIN request sock on syn cookies

2020-07-09T07:39:32+00:00

[ Upstream commit 9e365ff576b7c1623bbc5ef31ec652c533e2f65e ]

Currently any MPTCP socket using syn cookies will fallback to
TCP at 3rd ack time. In case of MP_JOIN requests, the RFC mandate
closing the child and sockets, but the existing error paths
do not handle the syncookie scenario correctly.

Address the issue always forcing the child shutdown in case of
MP_JOIN fallback.

Fixes: ae2dd7164943 ("mptcp: handle tcp fallback when using syn cookies")
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

rxrpc: Fix afs large storage transmission performance drop

2020-07-09T07:39:32+00:00

[ Upstream commit 02c28dffb13abbaaedece1e4a6493b48ad3f913a ]

Commit 2ad6691d988c, which moved the modification of the status annotation
for a packet in the Tx buffer prior to the retransmission moved the state
clearance, but managed to lose the bit that set it to UNACK.

Consequently, if a retransmission occurs, the packet is accidentally
changed to the ACK state (ie. 0) by masking it off, which means that the
packet isn't counted towards the tally of newly-ACK'd packets if it gets
hard-ACK'd.  This then prevents the congestion control algorithm from
recovering properly.

Fix by reinstating the change of state to UNACK.

Spotted by the generic/460 xfstest.

Fixes: 2ad6691d988c ("rxrpc: Fix race between incoming ACK parser and retransmitter")
Signed-off-by: David Howells 
Signed-off-by: Sasha Levin

rxrpc: Fix race between incoming ACK parser and retransmitter

2020-07-09T07:39:29+00:00

[ Upstream commit 2ad6691d988c0c611362ddc2aad89e0fb50e3261 ]

There's a race between the retransmission code and the received ACK parser.
The problem is that the retransmission loop has to drop the lock under
which it is iterating through the transmission buffer in order to transmit
a packet, but whilst the lock is dropped, the ACK parser can crank the Tx
window round and discard the packets from the buffer.

The retransmission code then updated the annotations for the wrong packet
and a later retransmission thought it had to retransmit a packet that
wasn't there, leading to a NULL pointer dereference.

Fix this by:

 (1) Moving the annotation change to before we drop the lock prior to
     transmission.  This means we can't vary the annotation depending on
     the outcome of the transmission, but that's fine - we'll retransmit
     again later if it failed now.

 (2) Skipping the packet if the skb pointer is NULL.

The following oops was seen:

	BUG: kernel NULL pointer dereference, address: 000000000000002d
	Workqueue: krxrpcd rxrpc_process_call
	RIP: 0010:rxrpc_get_skb+0x14/0x8a
	...
	Call Trace:
	 rxrpc_resend+0x331/0x41e
	 ? get_vtime_delta+0x13/0x20
	 rxrpc_process_call+0x3c0/0x4ac
	 process_one_work+0x18f/0x27f
	 worker_thread+0x1a3/0x247
	 ? create_worker+0x17d/0x17d
	 kthread+0xe6/0xeb
	 ? kthread_delayed_work_timer_fn+0x83/0x83
	 ret_from_fork+0x1f/0x30

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tipc: Fix NULL pointer dereference in __tipc_sendstream()

2020-07-09T07:39:27+00:00

[ Upstream commit 4c21daae3dbc9f8536cc18e6e53627821fa2c90c ]

tipc_sendstream() may send zero length packet, then tipc_msg_append()
do not alloc skb, skb_peek_tail() will get NULL, msg_set_ack_required
will trigger NULL pointer dereference.

Reported-by: syzbot+8eac6d030e7807c21d32@syzkaller.appspotmail.com
Fixes: 0a3e060f340d ("tipc: add test for Nagle algorithm effectiveness")
Signed-off-by: YueHaibing 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tipc: fix kernel WARNING in tipc_msg_append()

2020-07-09T07:39:27+00:00

[ Upstream commit c9aa81faf19115fc2e732e7f210b37bb316987ff ]

syzbot found the following issue:

WARNING: CPU: 0 PID: 6808 at include/linux/thread_info.h:150 check_copy_size include/linux/thread_info.h:150 [inline]
WARNING: CPU: 0 PID: 6808 at include/linux/thread_info.h:150 copy_from_iter include/linux/uio.h:144 [inline]
WARNING: CPU: 0 PID: 6808 at include/linux/thread_info.h:150 tipc_msg_append+0x49a/0x5e0 net/tipc/msg.c:242
Kernel panic - not syncing: panic_on_warn set ...

This happens after commit 5e9eeccc58f3 ("tipc: fix NULL pointer
dereference in streaming") that tried to build at least one buffer even
when the message data length is zero... However, it now exposes another
bug that the 'mss' can be zero and the 'cpy' will be negative, thus the
above kernel WARNING will appear!
The zero value of 'mss' is never expected because it means Nagle is not
enabled for the socket (actually the socket type was 'SOCK_SEQPACKET'),
so the function 'tipc_msg_append()' must not be called at all. But that
was in this particular case since the message data length was zero, and
the 'send <= maxnagle' check became true.

We resolve the issue by explicitly checking if Nagle is enabled for the
socket, i.e. 'maxnagle != 0' before calling the 'tipc_msg_append()'. We
also reinforce the function to against such a negative values if any.

Reported-by: syzbot+75139a7d2605236b0b7f@syzkaller.appspotmail.com
Fixes: c0bceb97db9e ("tipc: add smart nagle feature")
Acked-by: Jon Maloy 
Signed-off-by: Tuong Lien 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tipc: add test for Nagle algorithm effectiveness

2020-07-09T07:39:27+00:00

[ Upstream commit 0a3e060f340dbe232ffa290c40f879b7f7db595b ]

When streaming in Nagle mode, we try to bundle small messages from user
as many as possible if there is one outstanding buffer, i.e. not ACK-ed
by the receiving side, which helps boost up the overall throughput. So,
the algorithm's effectiveness really depends on when Nagle ACK comes or
what the specific network latency (RTT) is, compared to the user's
message sending rate.

In a bad case, the user's sending rate is low or the network latency is
small, there will not be many bundles, so making a Nagle ACK or waiting
for it is not meaningful.
For example: a user sends its messages every 100ms and the RTT is 50ms,
then for each messages, we require one Nagle ACK but then there is only
one user message sent without any bundles.

In a better case, even if we have a few bundles (e.g. the RTT = 300ms),
but now the user sends messages in medium size, then there will not be
any difference at all, that says 3 x 1000-byte data messages if bundled
will still result in 3 bundles with MTU = 1500.

When Nagle is ineffective, the delay in user message sending is clearly
wasted instead of sending directly.

Besides, adding Nagle ACKs will consume some processor load on both the
sending and receiving sides.

This commit adds a test on the effectiveness of the Nagle algorithm for
an individual connection in the network on which it actually runs.
Particularly, upon receipt of a Nagle ACK we will compare the number of
bundles in the backlog queue to the number of user messages which would
be sent directly without Nagle. If the ratio is good (e.g. >= 2), Nagle
mode will be kept for further message sending. Otherwise, we will leave
Nagle and put a 'penalty' on the connection, so it will have to spend
more 'one-way' messages before being able to re-enter Nagle.

In addition, the 'ack-required' bit is only set when really needed that
the number of Nagle ACKs will be reduced during Nagle mode.

Testing with benchmark showed that with the patch, there was not much
difference in throughput for small messages since the tool continuously
sends messages without a break, so Nagle would still take in effect.

Acked-by: Ying Xue 
Acked-by: Jon Maloy 
Signed-off-by: Tuong Lien 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

seg6: fix seg6_validate_srh() to avoid slab-out-of-bounds

2020-07-09T07:39:27+00:00

[ Upstream commit bb986a50421a11bf31a81afb15b9b8f45a4a3a11 ]

The seg6_validate_srh() is used to validate SRH for three cases:

case1: SRH of data-plane SRv6 packets to be processed by the Linux kernel.
Case2: SRH of the netlink message received  from user-space (iproute2)
Case3: SRH injected into packets through setsockopt

In case1, the SRH can be encoded in the Reduced way (i.e., first SID is
carried in DA only and not represented as SID in the SRH) and the
seg6_validate_srh() now handles this case correctly.

In case2 and case3, the SRH shouldn’t be encoded in the Reduced way
otherwise we lose the first segment (i.e., the first hop).

The current implementation of the seg6_validate_srh() allow SRH of case2
and case3 to be encoded in the Reduced way. This leads a slab-out-of-bounds
problem.

This patch verifies SRH of case1, case2 and case3. Allowing case1 to be
reduced while preventing SRH of case2 and case3 from being reduced .

Reported-by: syzbot+e8c028b62439eac42073@syzkaller.appspotmail.com
Reported-by: YueHaibing 
Fixes: 0cb7498f234e ("seg6: fix SRH processing to comply with RFC8754")
Signed-off-by: Ahmed Abdelsalam 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

xprtrdma: Fix handling of RDMA_ERROR replies

2020-06-30T19:36:31+00:00

commit 7b2182ec381f8ea15c7eb1266d6b5d7da620ad93 upstream.

The RPC client currently doesn't handle ERR_CHUNK replies correctly.
rpcrdma_complete_rqst() incorrectly passes a negative number to
xprt_complete_rqst() as the number of bytes copied. Instead, set
task->tk_status to the error value, and return zero bytes copied.

In these cases, return -EIO rather than -EREMOTEIO. The RPC client's
finite state machine doesn't know what to do with -EREMOTEIO.

Additional clean ups:
- Don't double-count RDMA_ERROR replies
- Remove a stale comment

Signed-off-by: Chuck Lever 
Cc: 
Signed-off-by: Anna Schumaker 
Signed-off-by: Greg Kroah-Hartman